1. Field of the Invention
The present invention relates to image forming apparatuses, and control methods and programs thereof.
2. Description of the Related Art
In recent years, image forming apparatuses have been developed that can handle various types of print data. Since print data is created by a large number of users who use a wide range of applications, there are cases where, depending on the print data, its volume may be very large. Extremely large amounts of time are required to process print data containing large volumes of data, which is a cause of major reductions in performance. Further still, although there are cases where resolution or tone is reduced to avoid memory insufficiencies caused by using large volumes of memory, this is a cause of reductions in output quality. To avoid these problems, data is reused using a cache when identical sets of data are present, which reduces the amount of memory used and inhibits reductions in output quality. Further still, improved performance is achieved by improving efficiency in CPU caches during image rendering. Also, in regard to caches, it is possible to delete cache data that has become old to improve search efficiency (see Japanese Patent Laid-Open No. 2001-216110).
Image cache processing based on conventional methods involves carrying out arithmetic processing for comparing the content of the image data with the content of the cache that is currently being held, or carrying out processing for searching the cache with respect to all the image data contained in the print data. The aforementioned Japanese Patent Laid-Open No. 2001-216110 also requires executing cache processing on all data objects. Accordingly, in a case of processing PDL data containing large amounts of image data, cache-related processing increases, which unfortunately is a cause of reduced printing speeds.